1. Field of the Invention
The present invention relates to a recording method and a recording apparatus for a recording medium. More particularly, the present invention relates to a recording method and a recording apparatus for a recording medium having management data to manage a data recording and/or reproducing operation.
2. Background of the Invention
A disc-shaped data rewritable recording medium on which an user can freely record music data or the like has been hitherto known. This type of disc-shaped recording medium (hereinafter referred to as "disc") is provided with a data area on which music data of pieces of music have been already recorded, and a data area (user's Table Of Contents, hereinafter referred to as "U-TOC") on which management data to manage unrecorded areas having no data recorded therein are recorded. The disc is designed so that the management data are also rewritten in accordance with various operations such as a recording operation, an editing operation, a deleting operation, etc., for example.
For example, when a piece of music is recorded, a recording device searches a non-recording area on the disc on the basis of the management data in the U-TOC to record audio data in the searched non-recording area. On the other hand, a reproducing device searches from the U-TOC an area on which a piece of music (track) to be reproduced is recorded, and accesses the area to perform a reproducing operation.
A data recordable disc such as a magneto-optical disc has an advantage that a random access can be more easily performed as compared with a tape-shaped recording medium such as a DAT (digital audio tape), a compact cassette tape or the like. Accordingly, it is unnecessary to record music data (plural pieces of music) from the inner peripheral side to the outer peripheral side on the disc so that the respective music data are orderly arranged from a first track until an n-th track in this order. That is, even when the respective pieces of music are physically randomly recorded on the disc, the pieces of music can be orderly reproduced insofar as addresses from the first track to the n-th track at which the respective pieces of music are recorded are managed by the U-TOC as described above or the like. In the following description, one piece of music is assumed to be recorded on one track, however, one piece of music may be recorded over plural tracks or on a part of one track.
Furthermore, each piece of music (track) is not necessarily recorded as a lump on a continuous part (hereinafter, the term of "part" means a part on which physically-continuous data are recorded), and it may be discretely recorded on plural parts while divided into plural sub pieces of music (sub music data).
Particularly in a system for temporarily storing data read out from a magneto-optical disc into a buffer memory at a high transfer rate, then reading out the data from the buffer memory at a low transfer rate to obtain audio reproduction signals, and then conducting a decoding processing on the audio reproduction signals, the reproduction audio signals can be output without interruption even when the data read-out operation from the magneto-optical disc is temporarily intercepted due to access shift between parts.
Accordingly, by repeating a recording and reproducing operation and a high-speed access operation (an access operation which is finished within a reproducible time in accordance with a data accumulation amount which is dependent on the difference between a data writing rate into the buffer memory and a data reading rate from the buffer memory, the recording/reproducing operation of the pieces of music can be performed with no trouble even when the music datum of a piece of music is physically divided into plural sub music data and discretely recorded on the disc.
For example, a data recording format as shown in FIG. 1 may be adopted. In this data recording format, each of first and second pieces of music is physically continuously recorded on a part (for example, the first and second pieces of music are recorded on a part M.sub.1 and a part M.sub.2 respectively) while each of fourth and fifth pieces of music is discretely recorded on plural parts with being physically divided into plural sub music data (for example, the fourth piece of music is divisionally recorded on sub parts M.sub.4(1) to M.sub.4(4) and the fifth piece of music is also divisionally recorded on sub parts M.sub.5(1) to M.sub.5(2). FIG. 1 shows the recording format more schematically, and practically one part may extend over several to several hundreds rounds (tracks) or more.
When the music data recording or deleting operation is repetitively performed on the magneto-optical disc, empty areas occurs irregularly on the disc due to the difference in music rendering time between pieces of music to be recorded or between pieces of music to be deleted. However, with the data discrete recording operation as described above, for example, a piece of music which is longer than a deleted piece of music can be partially or wholly recorded on a part on which the deleted piece of music was recorded, so that the data recording area can be effectively used (occurrence of vain data recording areas can be suppressed) by repeating the data recording/deleting operation. The data to be recorded on the disc are not limited to "pieces of music (musical data)", and any data may be recorded insofar as these data are audio (sound) signals. In the following description, it is assumed that a piece of music is recorded as an unit data (track) whose content is continuous.
Of course, it is required that the data recording operation on such a disc is continued while accessing plural parts serving as non-recording areas, and the data reproducing operation from the disc is performed while accessing plural parts so that each piece of music is reproduced accurately continuously. In order to satisfy this requirement, data for linking parts for each piece of music, for example, the parts M.sub.4(1) to M.sub.4(4) shown in FIG. 1, and data indicating non-recording areas are held as management data in the U-TOC which is rewritten every recording operation or deleting operation as described above. Accordingly, the recording and/or reproducing apparatus is controlled to read in the management data from the U-TOC to access the head of the data, whereby a proper recording/reproducing operation is performed.
FIG. 2 shows a data recording format on the disc. As shown in FIG. 2, the recording data on the disc are blocked (sectioned) on a cluster basis. One cluster CL (=36 sectors) contains a sub data area of four sectors (1 sector=2352 bytes) and a main data area of 32 sectors, and one cluster is the minimum unit for recording. One cluster corresponds to a track of two to three rounds. An address is recorded every sector.
The sub data area of four sectors is used for sub data or as a linking area, and the management data, audio data, etc. are recorded on the main data area of 32 sectors.
One sector is further divided into sound groups (not shown), and two sectors are divided into 11 sound groups. Data of 512 samples are recorded in a sound group while shared to an L-channel and an R-channel. Each sound group has an audio data amount corresponding to a time of 11.6 msec.
There have been utilized two recording methods when an user records pieces of music, voices or the like using a disc system using a buffer memory as described above. In one recording method, a non-recording area on which no data are recorded (hereinafter referred to as "free area") is automatically searched, and the recording operation is performed on the searched free area. On the other hand, in the other recording method, the deletion of past data is started from a portion on which a recording start operation is conducted, that is, a so-called overwrite recording operation is performed. In this specification, the term "past data" means data to be deleted or disused.
The data overwrite recording operation will be described below with reference to FIGS. 3A to 3D. In this case, it is assumed that four pieces of music (music data M.sub.1 to M.sub.4) have been recorded on a disc as shown in FIG. 3A.
The data overwrite operation is performed, for example, in a case where an user starts the recording operation in an overwritable mode at the time when the reproduction of the first piece of music (first music data M.sub.1) is finished and the reproduction of the second piece of music (second music data M.sub.2) is about to start, or in a case where the head position of the second piece of music M.sub.2 is accessed to temporarily stop the reproducing operation of the second piece of music (second music data M.sub.2) and the recording operation is started in an overwritable mode. These cases correspond to a case where an user wants to delete the music data of the second piece of music and record the music data of a new piece of music, for example. That is, through this overwrite operation, a past piece of music on the disc is deleted in the same manner as that on a compact cassette tape, and a new piece of music is recorded on the deleted piece of music. In this specification, "past piece of music" means a piece of music to be deleted or disused.
Through this operation, in the disc system as described above, the head position of the second piece of music (second music data M.sub.2) and the subsequent portion thereof are wholly deleted and set to a free area as shown in FIG. 3B. Thereafter, the recording operation of actual data of a new second piece of music (new second music data M.sub.2) is started from the head position of the free area as shown in FIG. 3C. When a recording stop operation is performed at a time, the recording operation of the new second piece of music (new second music data M.sub.2) is completed.
However, the overwrite recording method as described above has a problem that those data which are still needed by the user may be unintentionally deleted because the whole portion subsequent to the recording start point is deleted. For example, even when the user newly records a piece of music whose rendition is finished within the total time of the pieces of music (music data M.sub.2 and M.sub.3) in FIGS. 3A to 3D because he wants to leave the fourth piece of music, the piece of music (music data M.sub.4) is deleted against his intention. If the user is familiar with the operation of the disc system, he would understand that the piece of music (music data M.sub.4) is deleted. However, if the user is familiar with the recording operation for a compact cassette tape, but unfamiliar with the disc system, he would operate the disc system in the same manner as the compact cassette tape, so that the above problem is liable to occur.
Furthermore, in a case where the user is familiar with the operation of the disc system and wants to delete the pieces of music (music data M.sub.2 and M.sub.3) while leaving the piece of music (music data M.sub.4) and overwrite a new piece of music on the deleted pieces of music (music data M.sub.2 and M.sub.3), the music data M.sub.4 is temporarily altered to the music data M.sub.2 by performing a music order changing edition, and then the recording is started from the head position of the music data M.sub.3. Therefore, the overwrite recording operation itself becomes cumbersome.
Still furthermore, the actual recording operation is not started just when the recording operation is instructed because an editing operation of setting the recording start point and the subsequent portion thereto as a free area must be performed before the recording operation is started. Therefore, it takes some time to start the actual recording operation.